DOI: 10.5194/cp-10-1221-2014
Scopus记录号: 2-s2.0-84903479013
论文题名: Dependence of Eemian Greenland temperature reconstructions on the ice sheet topography
作者: Merz N. ; Born A. ; Raible C.C. ; Fischer H. ; Stocker T.F.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 3 起始页码: 1221
结束页码: 1238
语种: 英语
Scopus关键词: air temperature
; climate modeling
; climate variation
; Eemian
; energy balance
; GRIP
; ice core
; ice sheet
; interglacial
; paleoclimate
; paleotemperature
; proxy climate record
; reconstruction
; sensible heat flux
; surface wind
; topographic effect
; wind velocity
; Arctic
; Greenland
; Greenland Ice Sheet
英文摘要: The influence of a reduced Greenland Ice Sheet (GrIS) on Greenland's surface climate during the Eemian interglacial is studied using a set of simulations with different GrIS realizations performed with a comprehensive climate model. We find a distinct impact of changes in the GrIS topography on Greenland's surface air temperatures (SAT) even when correcting for changes in surface elevation, which influences SAT through the lapse rate effect. The resulting lapse-rate-corrected SAT anomalies are thermodynamically driven by changes in the local surface energy balance rather than dynamically caused through anomalous advection of warm/cold air masses. The large-scale circulation is indeed very stable among all sensitivity experiments and the Northern Hemisphere (NH) flow pattern does not depend on Greenland's topography in the Eemian. In contrast, Greenland's surface energy balance is clearly influenced by changes in the GrIS topography and this impact is seasonally diverse. In winter, the variable reacting strongest to changes in the topography is the sensible heat flux (SHF). The reason is its dependence on surface winds, which themselves are controlled to a large extent by the shape of the GrIS. Hence, regions where a receding GrIS causes higher surface wind velocities also experience anomalous warming through SHF. Vice-versa, regions that become flat and ice-free are characterized by low wind speeds, low SHF, and anomalous low winter temperatures. In summer, we find surface warming induced by a decrease in surface albedo in deglaciated areas and regions which experience surface melting. The Eemian temperature records derived from Greenland proxies, thus, likely include a temperature signal arising from changes in the GrIS topography. For the Eemian ice found in the NEEM core, our model suggests that up to 3.1 °C of the annual mean Eemian warming can be attributed to these topography-related processes and hence is not necessarily linked to large-scale climate variations. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49252
Appears in Collections: 气候变化与战略
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Recommended Citation:
Merz N.,Born A.,Raible C.C.,et al. Dependence of Eemian Greenland temperature reconstructions on the ice sheet topography[J]. Climate of the Past,2014-01-01,10(3)